1. Field of the Invention
The present invention relates to a plasma display panel, and more particularly, to a plasma display panel providing increased brightness over the entire screen while simultaneously reducing power consumption.
2. Description of the Related Art
FIG. 1 illustrates a plasma display panel 8 similar to one disclosed in U.S. Pat. No. 6,566,812, which is hereby incorporated by reference. The plasma display panel 8 includes a rear substrate 10, address electrodes 20 disposed on the rear substrate in parallel, a first dielectric layer 30 covering the address electrodes 20, a barrier rib 40 disposed on the dielectric layer 30 with a grid shape to define a light emitting cell 50, a front substrate 60, sustain electrode pairs 70 formed on a lower surface of the front substrate 60, a second dielectric layer 80 covering the sustain electrode pairs 70, and an MgO layer 90 covering the second dielectric layer 80. The MgO layer 90 improves durability of the second dielectric layer 80, and is not essential for operation. The plasma display panel 8 is manufactured by adhering the front substrate 60 to the rear substrate 10. A discharging gas (not shown) is provided in the light emitting cell 50 when the front substrate to and the rear substrates 10 are joined together, and a fluorescent substance is formed on the lateral surface of barrier rib 40 and the upper surface of the first dielectric layer 30. Ultraviolet rays irradiate from the discharging gas due to the discharge between the electrodes, and the ultraviolet rays excite the fluorescent substance. The energy level of the fluorescent substance, now excited, is lowered by generating visible light rays.
FIG. 2 is a plan view of the plasma display panel shown in FIG. 1, wherein various layers of the plasma display panel are illustrated in shadow. The light emitting cell 50 is disposed above the address electrode 20, and a sustain electrode pair 70, including a data electrode (X1, X2, . . . , or Xn) and a scan electrode (Y1, Y2, . . . , or Yn), is disposed above the light emitting cell 50. Address discharging occurs between the scan electrode (Y1, Y2, . . . , or Yn) and a discharging portion (R1, R2, . . . , or Rn) of the address electrode 20 crossing the scan electrode (Y1, Y2, . . . , or Yn) In order for the discharging to occur, a sufficient amount of positive ions gather on the upper surface of the first dielectric layer 30 by the operation of address electrode 20, immediately before the address discharging occurs. Thus, the scan electrodes (Y1, Y2, . . . , or Yn) and the address electrodes 20 are reset immediately before address discharging occurs, so that the positive ions gather on the upper surface of the first dielectric layer 30.
As shown in FIG. 2, each of the discharging portions R1, R2, . . . , and Rn of the address electrodes 20 in the conventional plasma display panel 8 has the same area. When the areas of the discharging portions R1, R2, . . . , and Rn of the address electrodes 20 are equal and the discharging area is excessively large, power consumption increases greatly. On the other hand, if the discharging area is too small, the brightness of light emitted from a light emitting cell is not high enough where a subsequent scan electrode Ys and a subsequent discharging portion Rs are disposed; however, the brightness of light emitted from a light emitting cell is high enough where a preceding scan electrode Yp and a preceding discharging portion Rp are disposed.
Moreover, the brightness of light emitted from a light emitting cell is degraded where the subsequent discharging portion Rs is disposed because address signals are sequentially applied to the scan electrodes Y1, Y2, . . . , Yn. That is, while address discharging occurs between the preceding scan electrode Yp and a preceding discharging portion Rp due to a transmission of the address signal to the preceding scan electrode Yp, the subsequent scan electrode Ys and a subsequent discharging portion Rs are in a discharged state after reset. In this discharged state, positive ions gathered above the subsequent discharging portion Rs combine with electrodes, and thus, the amount of positive ions above the subsequent discharging portion Rs is not enough for address discharging to occur when address discharging should occur above the subsequent discharging portion Rs. Therefore, address discharging between the subsequent scan electrode Ys and the subsequent discharging portion Rs is degraded.